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Pals_1010 said:Source: GCSE Physics
"For a filament lamp, the temperature of the filament is most definitely not constant (it must to get hot in order to give out light!)
The resistance of a lamp's filament (the long, thin, coiled wire) increases dramatically as the current increases, resulting in the second graph below..
"
The second graph shows that the gradient decreases.
I/V = 1/R decreases.
So resistance increases....
yes you are right
and the variable resister would increase the current slowly slowly in the circuit so that a very high current would not pass through the bulb at once which would blow the bulb